Why are there so many charlatans in the Window Trade?

He won't know the details of the job until he sees it, i.e. accessibility, scale, etc.

Perhaps more importantly, he won't know who he'll be dealing with until he meets them in person. Some tradesmen, rightly, pick up on "bad vibes" from potential customers, i.e. awkwardness, arrogance, likely to be a pain in the arse, and either just walk away without providing a quote or quote a high price in the hope they don't want him, or if they do, at least he's getting extra money to put up with the likely problems/hassle of a difficult customer.

Because he has no way of knowing whether a job is even possible (and if it is possible, whether he can or wants to take it) until he goes and sees the property for himself.

He works alone so some jobs are simply too big and complex.
Some will take too much time and he can't book people in for 3-6 months (and then they don't want to wait that long).
Some can only be done in decent weather.
Some require the customer to arrange (for example) a skip, or scaffolding, or other trades to come in.

He's been working since he was 14 (for his dad originally, now runs his own business) - he knows what he's doing, has never had a complaint and has an excellent reputation, but he's not psychic and has no way of knowing whether a job is worth it (or even possible) until he visits the home and then sits down and works through the quote afterwards.

I got the biggest company in our area to quote for our small house - £16K. I wanted to laugh but suppressed it and said we'd be getting other quotes. The guy looked totally taken aback that we weren't accepting his quote there and then.

Got a small local company to do it for £6K.

We’ve just had our front door replaced, and it was mind-blowing how crap this industry is. Even when they bothered to respond to enquiries, it was all ‘can’t talk to the wife without the husband’ and the starting at a high price and negotiating down. It was like being back in the 80s.🤣 It might even have been all well and good if they’d actually had their showrooms open at the weekend for the hours they advertised on their own websites, but we’d drive there and they’d be closed.

Eventually found a relatively new husband & wife start-up who were fabulous. Happy to assume I might have been able to have a discussion with my husband when he wasn’t at work and agree what we were ordering, so I could go in all on my little own and order.

I had a new front door fitted in August. I picked a local company with good reviews that I had used decades previously for windows.

The boss did the quote, told him colour and glass decor and showed a picture of the type of door. He measured up and gave me the quote there and then and I confirmed the next day to have the door replaced.

I remember well the days of quotes where they stayed hours trying to get you to accept there and then after a call to "my manager" to see what they could do to reduce the price.

Shysters!